The Board of Adjustment shall consist of five (5) members who shall be residents of the City. Members shall be appointed for terms of five (5) years each, provided however, that members first (1st) appointed may be for varying periods so that succeeding terms will be staggered. Three (3) alternate members may be appointed to serve in the absence of or disqualification of the regular members. All members shall be appointed by the Mayor and approved by the Board of Alderpersons. Any vacancy in the membership shall be filled for the unexpired term by appointment by the Mayor and approval by the Board of Alderpersons. The Board of Alderpersons may remove any member of the Board of Adjustment for cause stated in writing and after public hearing.